Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major collagenous component secreted into the medium of cultured HT-1080 tumor cells was identified as type IV procollagen by specific antibodies and characteristic ratios of incorporated labeled 3-hydroxyproline and 4-hydroxyproline. The disulfide-bonded molecules consisted of two subunits, pro-alpha 1(IV) and pro-alpha 2(IV) chains with apparent molecular weights of 180 000 and 165 000. No conversion of the procollagen to collagen or to procollagen intermediates was detected in the cell cultures. The two subunits apparently represent different gene products, since enzymatic digestion of the separated chains produced quite different peptide maps. Pepsin degraded native type IV procollagen successively into several fragments, some still disulfide-linked, giving rise to a complex set of polypeptide chains (Mr = 30 000-140 000). This agrees with similar diverse patterns produced by pepsin from authentic type IV collagens. The ratio between the pro-alpha 1(IV) and pro-alpha 2(IV) chains varied in several experiments between 1.3 and 1.8, suggesting that the two chains belong to different triple-helical molecules. The cells also produced distinct amounts of fibronectin (subunit Mr = 230 000) and of the basement membrane glycoprotein laminin. The latter showed three subunits with Mr = 220 000, 210 000, and 400 000. A further disulfide-bonded, non-collagenous polypeptide (Mr = 160 000) was detected but not yet identified. Immunofluorescence demonstrated these proteins within the cells but not in a pericellular matrix. The production of basement membrane components by HT-1080 cells and lack of interstitial collagens disagree with the original classification of the cell line as a fibrosarcoma.
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PMID:Biosynthesis of two subunits of type IV procollagen and of other basement membrane proteins by a human tumor cell line. 625 Aug 36

Prolyl hydroxylase activity, hydroxyproline content and solubility of collagen in the human pregnant and post-partum uterus were studied. The results were as follows: 1. Prolyl hydroxylase activity in the uterine cervix was slightly elevated during pregnancy, and the highest level was observed on the 4th day post-partum. On the other hand, in the uterine body the highest activity was observed immediately after delivery. 2. Hydroxyproline content in the pregnant uterine cervix was slightly less than that of nonpregnant control and the lowest level was observed immediately after delivery, but on the 4th day post-partum it increased slightly. In the uterine body, there were no remarkable changes in content during pregnancy, but immediately after delivery it decreased remarkably. 3. Pepsin-soluble collagen in the uterine cervix increased significantly from an early pregnancy to immediately after delivery compared with nonpregnant control, but on the 4th day post-partum it decreased significantly compared with that immediately after delivery. In the uterine body, no significant changes in solubility were observed throughout pregnancy. 4. Comparing these data obtained on the cervix and the body at different stages of nonpregnancy, pregnancy and post-partum, enzyme activities in the body were always higher. Hydroxyproline content in the body of nonpregnant uterus showed a lower value than that in the cervix, but no remarkable differences were found between the cervix and the body throughout pregnancy and immediately after delivery. The significant decrease in pepsin-soluble collagen in the body was observed immediately after delivery.
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PMID:[Studies on prolyl hydroxylase activity, hydroxyproline content and solubility of collagen in the human uterus during pregnancy, delivery and postpartum involution (author's transl)]. 627 84

A collagenous glycoprotein (Mr 140000) was isolated from dissociative extracts of foetal bovine nuchal ligament and purified by a combination of ion-exchange and gel-filtration chromatography. This glycoprotein (designated MFPI) exists as a large-Mr disulphide-bonded aggregate in the absence of a reducing agent. The purified glycoprotein was shown to contain about 6% (w/w) carbohydrate, mostly as galactose, glucose and mannose. Amino acid analysis showed the presence of hydroxyproline and hydroxylysine, indicative of its collagenous nature. The collagenous nature of this glycoprotein was further investigated by enzyme digestion. Pepsin digestion produced three major fragments, which were identical with peptides of type VI collagen. Bacterial-collagenase digestion of the unreduced glycoprotein also produced several discrete peptides. However, reduction of the glycoprotein before bacterial-collagenase digestion resulted in the degradation of these discrete peptides. Glycoprotein MFPI extracted in dissociative conditions appears to be a larger-Mr form of type VI collagen, believed to originate from microfibrillar components in the intact tissue.
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PMID:A collagenous glycoprotein found in dissociative extracts of foetal bovine nuchal ligament. Evidence for a relationship with type VI collagen. 633 16

Pepsin extracted collagen and an acid soluble glycoprotein were purified from placentas of normal and diabetic human beings. Diabetic samples exhibit a significant increase in ketoamine-linked glucose whereas both amino acid and carbohydrate composition were unaffected. This excess non enzymatic condensation of glucose on free amino-groups was found to increase platelet aggregating potency of these proteins independently of any modification in fiber morphology.
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PMID:Non enzymatic glycosylation increases platelet aggregating potency of collagen from placenta of diabetic human beings. 640 73

Native type IV collagen was isolated from human placental tissue by pepsin digestion, fractional salt precipitation, reduction and alkylation, a second pepsin digestion, and chromatography on diethylaminoethyl- and carboxymethyl-cellulose. After denaturation, 10 distinct peptides were isolated from this material by molecular sieve, ion-exchange, and high-performance liquid chromatography. All of the peptides were found to have amino acid compositions characteristic of type IV collagen. Analysis of the eight major peptides by amino-terminal amino acid sequencing and by cyanogen bromide and tryptic peptide mapping has revealed the manner in which they are derived from type IV collagen. Pepsin liberates two large peptides by attacking non-triple-helical regions, one derived from the alpha 1 (IV) chain (F2, Mr 90 000) and one derived from the alpha 2 (IV) chain (F3, Mr 75 000). The alpha 1 (IV)-derived F2 peptide is also represented in the pepsin digest by amino-terminal and carboxy-terminal subfragments [F4c (Mr 41 000) and F4a (Mr 60 000)], as is the alpha 2 (IV)-derived F3 peptide [F5 (Mr 28 000) and F4b (Mr 50 000), respectively]. These findings indicate that the molecular regions from which the larger peptides are derived in themselves contain pepsin-sensitive (non-triple-helical) domains. In addition, several of the peptides examined were found to be present in two slightly different forms, suggesting that closely adjacent pepsin-sensitive sites often exist within the type IV collagen molecules. The methods outlined here provide a reliable means by which identifiable type IV collagen peptides can be isolated.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Isolation and characterization of pepsin-solubilized human basement membrane (type IV) collagen peptides. 641 91

A major extracellular matrix glycoprotein, GP140 , synthesized by WI-38 human lung fibroblasts has previously been shown to be collagen-like. A form of GP140 that is related to extracellular matrix GP140 both antigenically and in apparent molecular mass was isolated from human placenta. Types I-VI collagen were isolated from human tissues by limited pepsin digestion, selective salt precipitation, and chromatography. Immunoblot analysis of the collagens and GP140 utilizing affinity-purified polyclonal antiserum directed against extracellular matrix GP140 demonstrated cross-reactivity of antibodies with type VI collagen. Both type VI collagen and matrix GP140 could be digested with bacterial collagenase following reduction with dithiothreitol but were collagenase insensitive under nonreducing conditions, unlike types I-V collagen. Placental and matrix GP140 and type VI collagen were shown to have receptors for 125I-labeled Lens culinaris lectin. Pepsin digestion of WI-38 extracellular matrix GP140 yielded a 64,000-dalton band which co-migrated with subunits of reduced type VI collagen on Coomassie-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels, reacted with anti- GP140 antiserum and 125I-labeled L. culinaris lectin, and was collagenase-sensitive only under reducing conditions. CNBr fragmentation of extracellular matrix GP140 , the 64,000-dalton pepsin-resistant peptide of GP140 and type VI collagen followed by immunoblot analysis using anti- GP140 revealed similarities in peptide maps of GP140 and type VI collagen. Our data strongly suggest that GP140 and type VI collagen share characteristics that differ from those of other collagen types and that intermolecular disulfide bonding appears to stabilize these molecules in their native unreduced form, thus conferring collagenase resistance. Finally, the SC1 and SC2 subunits of type VI collagen appear to be generated by pepsin digestion of GP140 .
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PMID:Pepsin-generated type VI collagen is a degradation product of GP140. 642 26

The 140 000-dalton collagenous glycoprotein (CGP) from calf aorta and ligament characterized by Gibson & Cleary (1982) [Gibson, M.A., & Cleary, E.G. (1982) Biochem. Biophys. Res. Commun. 105, 1288-1295] has been studied. In the electron microscope, rotary-shadowed CGP molecules appear similar to the dimers of type VI collagen (short-chain collagen, intima collagen) described by other authors [Furthmayr, H., Wiedemann, H., Timpl, R., Odermatt, E., & Engel, J. (1983) Biochem. J. 211, 303-311] except that they have larger globular domains. As shown by gel electrophoresis, pepsin treatment of CGP at 4 degrees C either before or after reduction releases polypeptide chains corresponding in size to those of type VI collagen. Electron microscopic examination shows that pepsin digestion of nonreduced CGP removes the outer globular domains, reduces the size of the inner ones, and separates the paired central strands. The residual structures look like type VI collagen dimers. When intact CGP is reduced, monomers with two large globular ends are obtained. Pepsin digestion of monomers removes most or all of both globular domains. In immunoblots, CGP and its pepsin-derived fragments react with antibodies directed against type VI collagen. The results indicate that type VI collagen is an integral component of CGP.
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PMID:A collagen-like glycoprotein of the extracellular matrix is the undegraded form of type VI collagen. 643 75

Macromolecular collagen components in normal liver and at the different stages of human liver cirrhosis were studied under various extraction conditions. The collagen content at the typical stage of liver cirrhosis was more than five-fold higher than that of the normal state. Pepsin-solubilized collagens extracted successively accounted for 90% of the total collagen and were subjected to determination of the collagen types by salt differentiated fractionation and SDS-polyacrylamide gel electrophoresis. Both type I and III collagens, especially the former, increased, reflecting enhanced total collagen with the progression of liver cirrhosis. The ratio of type I to type III was 1.02 - 1.22 in normal liver and at the early stage of liver cirrhosis, but increased to 1.58 and 1.60 at the typical and advanced stages of liver cirrhosis, respectively. At the early stage, the remarkable increase in type V collagen started much earlier than at the typical stage when the ratio of type I to type III changed. The enhancement of type V collagen may result from a cell proliferative phenomenon at the earlier stage of liver cirrhosis.
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PMID:Changes of collagen types at various stages of human liver cirrhosis. 643 88

Pepsin-soluble collagen was extracted from three histologically proven cases of chordoma and nucleus pulposus. The collagen types of these materials were investigated by differential salting-out, SDS-PAGE (sodium dodecyl sulphate-polyacrylamide gel electrophoresis) of native collagen and their CNBr (cyanogen bromide) cleaved peptides, and their amino acid compositions. Although the collagen of nucleus pulposus was type II, that of chordoma was largely type I. Collagen of notochord, the origin of nucleus pulposus, is known to be type II. Further investigation is necessary in view of the fact that collagen of chordoma, a tumor believed to be derived from notochord, is not type II.
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PMID:Type of collagen in chordoma. 643 58

Fibril formation of neutral salt soluble and pepsin-treated type I collagen from rabbit corneal stroma or sclera was compared using a turbidimetric analysis which permits the determination of apparent rate constants and activation energies for the lag and growth phase of collagen fibrillogenesis. Information regarding the lateral growth of fibrils was obtained from the final turbidity values. Neutral salt soluble corneal collagen had smaller rate constants for both the lag and growth phases of fibrillogenesis than scleral collagen. Pepsin treatment decreased the rate constants for both collagens proportionately. The activation energies were higher for type I collagen from cornea than sclera. Pepsin treatment increased the activation energy for both phases of corneal fibril formation but only the growth phase of scleral collagen fibrillogenesis was affected. The extent of lateral fibril growth was compared using the intrinsic turbidity values which are related to the mass per unit fibril length. Neutral salt soluble scleral type I collagen had a significantly higher intrinsic turbidity than did neutral salt soluble corneal collagen indicating that scleral collagen formed thicker fibrils; however, this difference was not retained after pepsin treatment, demonstrating that a helical-telopeptide interaction occurs in corneal type I collagen which influences fibril diameter. The observed differences in the rate constants, activation energies and intrinsic turbidity values indicates that there are molecular differences which are responsible for fibrillar differences of corneal and scleral type I collagens.
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PMID:Kinetic analysis of collagen fibrillogenesis: II. Corneal and scleral type I collagen. 647 70


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